Electric Performance

German based specialist sports car manufacturer Ruf Automobile GmbH has demonstrated that battery powered vehicles need not be merely clean, green and sensible. The latest electric concept vehicle to come from company managing director Alois Ruf delivers a level of performance that puts many petrol engine sports cars to shame.

The eRUF Model A concept vehicle was unveiled on October 10, 2008. Based upon the Porsche 911, the Ruf creation to all appearances looks just like every other 911 built at the Porsche factory in Zuffenhausen, near Stuttgart. Lurking within the engine compartment, however, is not the familiar six-cylinder, 3.6-litre boxer engine. In its place sits a 150 kW/204 hp three-phase AC motor capable of producing a maximum 650 Nm of torque.

Providing ‘juice’ to the engine is 96 lithium-ion, ion phosphate base batteries produced by UK based manufacturer Axeon. Each of the batteries weighs 5.6 kilograms and delivers 160 Ah. The battery system is constantly monitored by an Axeon intelligent bus system. Each individual cell is coupled with a sensor that sends critical information on cell temperature and voltage to the central control system. If irregularities appear during operation, the system can react within milliseconds to bring the values back in line, effectively preventing critical lithium-ion overheating behaviour during charging.

What sets the eRUF aside from the average electric car is what it can do. Admittedly, the concept car’s performance isn’t fully on par with a regular 911 Carrera – but then again it is not so far off, either. Pressing the pedal to the floor will see the electric car (when its development target is reached) accelerate from 0 to 100 km/h in under seven seconds, and it will keep on going up to a maximum speed of 225 km/h (160 mph). Depending on how it is driven, the eRUF has a range between around 250 and 320 km.

In terms of efficiency, however, the eRUF leaves the standard 911 in its dust. As Ruf comments, a highly-developed, modern petrol engine uses around 75 per cent of the energy in its tank to heat the engine coolant and exhaust gas and only 25 to 30 per cent for actual propulsion. The permanent magnet electric motor, on the other hand, offers over 80 per cent efficiency over the majority of its power range, extending to 90 per cent in the upper end of its power range.